with the 50k-60k budget for an SQL, it will be hard to fit if you are planning on a full blown audio SQL. siguro the best is to lessen the SQ para makapasok sa budget. lets not think of electronic crossover, 3 way seps, etc.

IMO you can fit that budget sa full blown SQL if your willing to go down on brands (and i mean really go down) like ryan audio, etc.

but i personally say, if you can afford higher quality brands, go for it.

for me:
memphis audio for the seps
kahit pioneer na lang rear fill (powered by the HU)
rockford fosgate amp to power both seps and subs
JL audio or MTX for the subs (depending on your taste)
minimal woodwork

this is not a full SQL setup pero basic SQ with a little power on the subs. power hungry mga ito kaya put on a capacitor kahit 1 farad para mahabol yung bass.